You must scan the QR code, click continue to attach the screenshot (it is the only proof of payment) and you can complete the purchase.
One fine winter morning I was on a safari at Kanha national park. While clicking a few photos of deer on a misty morning I thought to click an image to show the moment in the jungle and how it feels so I just focused on the plant in the foreground and clicked this to show that someone is here in a different way.